1. Field of the Invention
The present invention relates to a variable cutoff folding device capable of handling a change in cutoff (cutting length) of a continuous paper, and a printer comprising the variable cutoff folding device.
2. Description of the Related Art
In a conventional rotary press, in order to change cutoff in a direction of continuity of a continuous paper, it is necessary to exchange the likes of a printing plate or a plate cylinder on which the printing plate is mounted, so that realistically cutoff could not be easily changed.
To counter this, a digital printer disclosed in Patent Document 1 identified below has become publicly known. The digital printer disclosed in Patent Document 1 differs from a rotary press in not requiring a printing plate. It is therefore possible to easily carry out a change in cutoff in a direction of continuity of the continuous paper.
In addition, a folding device disclosed in Patent Document 2 identified below has become publicly known. The folding device disclosed in Patent Document 2 is capable of collect folding that allows overlapping of sheets on an outer circumferential surface of a folding cylinder to be performed to an amount of a desired number.
The folding device disclosed in Patent Document 2 is a folding device that protrudes a pin of a pin device installed in the folding cylinder from the outer circumferential surface of the folding cylinder, stabs the pin into a leading edge in a running direction of a cut sheet (cut sheets), wraps the sheet(s) on the outer circumferential surface of the folding cylinder while holding the sheet(s), operates a thrust blade device installed in the folding cylinder, at a position of minimum distance between the folding cylinder and a jaw cylinder, based on a predetermined operating signal, and, simultaneously to causing a middle portion of the sheet(s) to be gripped by a jaw device installed in the jaw cylinder, retracts the pin of the pin device to release the held sheet(s), thereby producing a signature.
However, in the folding device disclosed in Patent Document 2, there was a problem that circumferential length of the folding cylinder does not change, hence when cutoff of the continuous paper is changed, a cycle of the folding cylinder making a single rotation and a sheet spacing of continuously supplied cut individual sheets are not synchronous, whereby it becomes impossible to continuously wrap the individual sheets at an accurate wrapping position.
Accordingly, there appears a folding device, of the kind disclosed in Patent Document 3 identified below, that, accompanying a change in cutoff, adjusts timing when wrapping the cut sheets on the folding cylinder. (Hereinafter, this folding device is referred to as a “variable cutoff folding device”.) The conventional variable cutoff folding device disclosed in Patent Document 3 comprises a printing device, a cutting device and a processing device, and, furthermore, comprises a first conveyor belt device and a second conveyor belt device between the cutting device and the processing device. The conventional variable cutoff folding device including these devices is configured to cut the web supplied from the printing device after changing the cutting length of said web and set a conveying speed of said web to a speed that accords with the cutting length of the sheets cut by the cutting device, and at the same time to set a sheet conveying speed in the first conveyor belt device to have an equal speed to that of the web conveying speed. Furthermore, the conventional variable cutoff folding device is configured to, when receiving said sheets from the first conveyor belt device by means of the second conveyor belt device, receive the sheets with the same speed as the sheet conveying speed in the first conveyor belt device, then change the sheet conveying speed during conveyance of the sheets and, when transferring the sheets to the processing device, transfer the sheets with the same speed as the sheet conveying speed in the processing device.
[Patent Document 1] JP 2011-157168 A
[Patent Document 2] JP 2012-144370 A
[Patent Document 3] JP 4191732 B2